Bio 100 Second Exam

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Which statement accurately summarizes a difference between ribonucleotides and deoxyribonucleotides?

Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location.

The condensation reaction that forms nucleic acid polymers occurs between a _____ group on one nucleotide and a _____ group on a second nucleotide.

phosphate, hydroxyl

In a nucleic acid polymer, the hydrogen bonds that help to hold regions of double-strandedness together occur between what parts of the nucleotide monomers?

nitrogenous bases

DNA is composed of building blocks called _____.

nucleotides

In eukaryotic cells DNA has the appearance of a _____.

double helix

The proteome is all the proteins produced by an organism. The genome is the totality of all genes of an organism. If the proteome is much larger than the genome, which of the following statements would be accurate?

At least in some cases, a single gene must code for more than one protein.

Which answer best explains why errors in transcription might lead to changes in a cell's phenotype?

Changes in mRNA base sequence might result in changes in amino acid sequences of proteins.

All three domains (Bacteria, Archaea, and Eukarya) follow the same genetic code. Which of the following statements would most likely be accurate given that information?

The genetic code evolved before the different domains diverged.

Which of the following findings violated the central dogma?

the discovery of RNA viruses that synthesize DNA using reverse transcriptase

Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)?

One addition and one deletion mutation.

The redundancy of the genetic code is a consequence of _____.

having more codons than amino acids

When an amino acid is specified by more than one codon, what is usually shared by the set of codons that specifies this amino acid?

the first and second bases

What does it mean when we say the genetic code is redundant?

More than one codon can specify the addition of the same amino acid.

The central dogma has been challenged on several levels (e.g., the discovery of RNA viruses, which use their RNA to directly synthesize proteins; and the discovery of reverse transcriptase, which makes DNA from RNA). Which of the following is another example of an exception to the central dogma?

Prions are infectious protein molecules capable of altering the folding of normal proteins.

A point mutation that results in the substitution of one amino acid for another within a protein is a _____.

missense mutation

Which statement best explains why some changes in DNA sequence do not change the corresponding protein?